'Dog owners need to beware of foxes because they’re getting more and more urbanised.'

Ms Reeves today warned other dog owners about the danger of foxes.

Lucky: The urban fox was not scared at all when Lexi's owner came to protect her, leaving the dog with deep wounds

She said: 'I was really shocked a fox could do this. Lexi could have been killed.

'Now people are using wheelie bins, foxes are finding it harder to track down food so they’re getting desperate and people need to watch their dogs.

'People must not encourage foxes by feeding them, because they’ll keep coming back.'Attacks by urban foxes on animals and even humans are on the increase.

In May 2010 nine-month-old twins Lola and Isabella Koupparis had to spend a week in hospital after a fox crept into their cots at their home in Hackney, east London, and savaged their arms as they slept.

Last year sleeping London student Mario Castilli woke up with a shock to find a fox biting him on the face while he lay in bed in his attic bedroom.

Scores of small dogs, kittens and other pets have also been attacked or killed in recent years in Britain's towns and cities.